Dov Soffer

Mutations in the Fatty Acid 2-Hydroxylase Gene Are Associated with Leukodystrophy with Spastic Paraparesis and Dystonia

Myelination is a complex, developmentally regulated process whereby myelin proteins and lipids are coordinately expressed by myelinating glial cells. Homozygosity mapping in nine patients with childhood onset spasticity, dystonia, cognitive dysfunction, and periventricular white matter disease revealed inactivating mutations in the FA2H gene. FA2H encodes the enzyme fatty acid 2-hydroxylase that catalyzes the 2-hydroxylation of myelin galactolipids, galactosylceramide, and its sulfated form, sulfatide. To our knowledge, this is the first identified deficiency of a lipid component of myelin and the clinical phenotype underscores the importance of the 2-hydroxylation of galactolipids for myelin maturation. In patients with autosomal-recessive unclassified leukodystrophy or complex spastic paraparesis, sequence analysis of the FA2H gene is warranted.

Mast cells in experimental allergic encephalomyelitis: characterization, distribution in the CNS and in vitro activation by myelin basic protein and neuropeptides.

Mast cells (MC) have been implicated in the pathogenesis of experimental allergic encephalomyelitis (EAE). In order to further evaluate their role, several morphological and functional studies were performed. Semiquantitative counts of histological sections showed a significant reduction in MC numbers in EAE brains. In addition, a higher proportion of EAE MC (about 50-70%) appeared degranulated compared with about 20% degranulation in controls. Central nervous system (CNS) MC exhibited staining properties of connective tissue MC and about 98% of them, both in diseased and control rats, were located in the thalamus. They were not present in the spinal cord and did not relate to EAE lesions. In vitro incubation of peritoneal MC (of connective tissue phenotype) with either MBP, or with neuropeptides such as substance P or bradykinin resulted in release of beta-hexosaminidase and histamine. The latter responses were similar in both EAE and control rats. It is suggested that the decrease in number and in granular content of CNS MC in EAE may reflect prior in vivo activation. The fact that MC were activated by MBP and by neuropeptides in vitro suggests a possible mechanism of MC activation in EAE.

Splicing mutation in dysferlin produces limb-girdle muscular dystrophy with inflammation.

Mutations in dysferlin were recently described in patients with Miyoshi myopathy, a disorder that preferentially affects the distal musculature, and in patients with Limb-Girdle Muscular Dystrophy 2B, a disorder that affects the proximal musculature. Despite the phenotypic differences, the types of mutations associated with Miyoshi myopathy and Limb-Girdle Muscular Dystrophy 2B do not differ significantly. Thus, the etiology of the phenotypic variability associated with dysferlin mutations remains unknown. Using genetic linkage and mutation analysis, we identified a large inbred pedigree of Yemenite Jewish descent with limb-girdle muscular dystrophy. The phenotype in these patients included slowly progressive, proximal, and distal muscular weakness in the lower limbs with markedly elevated serum creatine kinase (CK) levels. These patients had normal development and muscle strength and function in early life. Muscle biopsies from 4 affected patients showed a typical dystrophic pattern but interestingly, in 2, an inflammatory process was seen. The inflammatory infiltrates included primarily CD3 positive lymphocytes. Associated with this phenotype, we identified a previously undescribed frameshift mutation at nucleotide 5711 of dysferlin. This mutation produced an absence of normal dysferlin mRNA synthesis by affecting an acceptor site and cryptic splicing. Thus, splice site mutations that disrupt dysferlin may produce a phenotype associated with inflammation.

The anatomic basis of visual agnosia

In a patient with associative visual agnosia without alexia, there was bilateral infarction in the distribution of the posterior cerebral arteries, with corticosubcortical lesions in both occipitotemporal regions, sparing the corpus callosum. Bilateral loss of visual-limbic connections may underlie associative visual agnosia, and bilateral lesions of the inferior longitudinal fasciculi may be the necessary and sufficient lesions for this syndrome. Alexia was absent in this case, perhaps because the corpus callosum was intact.

Hereditary inclusion body myopathy The Middle Eastern genetic cluster

Background: Recessively inherited hereditary inclusion body myopathy (HIBM) with quadriceps sparing was initially described only in Jews originating from the region of Persia. The recent identification of the gene responsible for this myopathy and the common “Persian Jewish mutation” (M712T) enabled the re-evaluation of atypical phenotypes and the epidemiology of HIBM in various communities in the Middle East. Objective: To test for the M712T mutation in the DNA from HIBM patients in the Middle East. Methods: DNA from all suspected HIBM patients was tested for the M712T mutation. Unaffected members of families with genetically proven HIBM were studied too. In the majority of families, haplotype construction with markers spanning the 700-kb region of the HIBM gene was performed. Results: One hundred twenty-nine HIBM patients of 55 families (Middle Eastern Jews, Karaites, and Arab Muslims of Palestinian and Bedouin origin) were homozygous for the M712T mutation, and all carried the same haplotype. Five clinically unaffected subjects were also homozygous for the common mutation and haplotype, including two older adults (ages 50 and 68 years). Atypical features with this same mutation were marked quadriceps weakness in five patients, proximal weakness only in two patients, facial weakness in three patients, and a muscle biopsy showing perivascular inflammation in one patient. Conclusions: The phenotypic spectrum of recessive HIBM is wider than previously described, and the diagnostic criteria for this myopathy must be changed. The Middle Eastern cluster is the result of a founder mutation, with incomplete penetrance, that is approximately 1,300 years old and is not limited to Jews.

Intracranial meningiomas after high‐dose irradiation

Three patients who presented with intracranial meningiomas 12, 15, and 20 years, respectively, after therapeutic high‐dose irradiation of a primary brain tumor are described. Analysis of these cases and similar documented cases suggests that meningiomas after high‐dose irradiation constitute a recognizable entity. Patients with such tumors received radiation therapy at a young age (mean, age, 9.4 years). After a latent period of 2 to 47 years (mean, 19.8 years) they developed meningiomas at the site of irradiation, at a much younger age than patients with “spontaneous” meningiomas. Similar to the situation with meningiomas after low‐dose irradiation, a relatively high proportion of meningiomas induced by high‐dose irradiation tend to be malignant and biologically aggressive. A very young age at the time of irradiation seems to predispose to the induction of malignant meningiomas, rather than benign tumors. These unusual features provide indirect evidence that high‐dose radiation may play a role in the pathogenesis of meningiomas.

Alpha-fetoprotein Suppresses Experimental allergic Encephalomyelitis

Experimental allergic encephalomyelitis (EAE), induced in guinea pigs by immunization with myelin basic protein (MBP) or whole CNS homogenate was successfully treated, as well as partially prevented, by daily administration of fetal alpha-fetoprotein (alpha FP). alpha FP which is produced in high quantities during pregnancy can inhibit both the cell-mediated immune response to MBP and the binding of MBP antibody to the antigen in vitro. It has a non-specific immunosuppressive effect on both the cellular and humoral responses. It is suggested that the ability of alpha FP to suppress an experimental autoimmune disease, as presented in this model of EAE, indicates that clinical remissions of human autoimmune disease during pregnancy may be attributed to the effect of this natural substance.

Striatal degeneration and spongy myelinopathy in glutaric acidemia

The neuropathological findings in a 6 1/2-year-old boy with glutaric acidemia (GA) are described, and the pathology of 7 additional literature cases is briefly reviewed. Bilateral striatal degeneration and spongy change of the white matter were the salient features in this case and seem to represent the cardinal pathological features of the disease. Spongy myelinopathy was the result of intramyelinic vacuolation due to splitting of the myelin sheath along the intraperiod line, as illustrated here for the first time in GA. Based on morphological, biochemical and pharmacological data from humans and experimental animals, it is hypothesized that excitotoxin-mediated neuronal damage may account for the striatal degeneration, while toxic effect on myelin metabolism by the metabolic derangement of GA may explain the widespread white matter changes.

Neuronal intranuclear hyaline inclusion disease presenting as Friedreich's ataxia

SummaryA case of neuronal intranuclear hyaline inclusion disease (NIHID) is described, and the literature on seven reported cases is briefly reviewed. The patient was a 24-year-old man who died of a chronic progressive neurologic disease starting at the age of 6 years. Clinically, the disease presented as Friedreichss ataxia, and pathologically it was characterized by multisystem atrophy. An outstanding feature was the presence of widespread intranuclear hyaline inclusions in neurons of the brain, spinal cord, and myenteric plexus of the gut. The inclusions displayed yellow-green autofluorescence under ultraviolet (UV) light and were filamentous ultrastructurally. It seems that cases bearing such peculiar neuronal inclusions represent a distinct disease entity of unknown origin. The disease, which is sometimes familial, usually starts in childhood and affects both sexes. Clinically, it presents as multisystem degeneration with progressive ataxia as the prominent feature. Pathologically, it is characterized by neuronal loss, fiber tract atrophy, and intranuclear neuronal inclusions. In some cases such inclusions were found also in neurons of the myenteric plexus. Since these are accessible to biopsy it is recommended that rectal biopsy be made in every case of “atypical” system atrophy.

Epidemiology of Guillain‐Barré syndrome

From 1969 through 1972, a nationwide search for cases of Guillain-Barré syndrome (GBS) in Israel revealed 89 patients. The average annual age-adjusted incidence was 0.75 per 105 persons. Overall incidence of the syndrome was similar in Jewish groups of diverse ethnic backgrounds. Arabs had a lower overall incidence than Jews (0.46 per 105 persons), perhaps attributable to fewer Arabs at risk in older age groups. Peaks of incidence occurred among individuals over 60 and under 4 years of age when all cases were combined. No clear seasonal or geographic clustering of GBS was evident in Israel during the 4 years of this study. The incidence of GBS in the present study agrees with previous population-based estimates.